Description:The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!Jack and Annie arrive on the one continent they haven’t visited before: Antarctica! What can they hope to learn about happiness in such a barren place? Only the penguins know for sure…Jack and Annie are about to find out!Formerly numbered as Magic Tree House #40, the title of this book is now Magic Tree House Merlin Mission #12: Eve of the Emperor Penguin.Did you know that there’s a Magic Tree House book for every kid?Magic Tree House: Adventures with Jack and Annie, perfect for readers who are just beginning chapter booksMerlin Missions: More challenging adventures for the experienced readerSuper Edition: A longer and more dangerous adventureFact Trackers: Nonfiction companions to your favorite Magic Tree House adventuresHave more fun with Jack and Annie at MagicTreeHouse.com